Electrical heating device



, A. J. KERCHER ET AL ELEC'IRICAL` HBATENG DEVICE FMCG Juge WITNESS Patented Apr. 29, 1924.

UNITED STATES Pn'remvv orifice? ARTHUR J; KERCHER, 0F BERXLEY, ANI) XVILLIAM WESL EY HICKS, SAbl' FBANCISCC, CALIFOANIA.

ELECTRCAL HEAT ING DEVICE.

Application led June 5,

To all wlmi/Lit may concer/i 15e it known that we, An'smjn J. Knnonnn, and "ILLMM vVEsLEY limits, citizens of the United States, und residents, reepefftively, of the city oferkeley. county of Alameda, in the Htnte of' (nlifornia. and the City and county of Sun l*`ri1ricis(fo, in thel State of talit'ornia, have invented e new :and use# fui lllcetricnl Heating Device, ot' which the following is a speciiczition.

)ur invention relates to n heating unit, und more particularly to a hot plate, such :is .used .either lin Connection with' electrical ranges, or as separate units for ordinary household cooking. It is one of the objects of our invention 'to provide such n' device that will cause suhstniitially'all of the heut. generated bythe heatipgjcoils to he conducted tothe surface exposed `for usein cooking. Another object of our invention is to render the heating coils readil "renewable, sothat if any of them shouldl burned out, there would he no .necessity for discarding lthe entire hot plate g Uur invention possesses other advantageous features, some of which, with the foregoing, will be setY forth at length inthe following specification Where we shall outline in full that form ofthe invention which we have selected for illustration in the drawings accompan ing and 'forming part of our present speci lcation. In the drawings We have shown one embodiment of our invention7 but it is to be understood that We'doI not limitourselves to that form, since the-imvention as expressed in the claims mayhe embodied in other forms as well.

Referringto the drawings: v

Figure 1 is a side view` of the hot plate with the bottom cover removed;

Fig. 2 is a sectional view of the h ot plate showing l the corniguration of the metal around the heating elements;

Fig. 3 is a view from the bottom of the. device; and

Fig. 4 isv a side view from line 4-4`ofe hotpiate 11 is conveniently made from s casting,. s ueh as iron, steeLor any other goedv conductor of heat. This `plate has a surface-12 upon which the article to be heated is placed. Extending transversely of the plate and below the surface 12 are a 1922, seria: Na. 565,305.

plurality oi apertures l eieinents'ure .vounrl on lone; spools, und oon,- Sist of the proper length und size of resist ence Wire.

The dperturee` l :ire formed either in;

costing or driliintnin Vhi; portion i5, of the l which serve tov eornmodute the heating elements l1. These L hot plate. This 'portion sones :is the honS- One of the iinpf-n'tunt features of our invention 1s the coniigqurnmon of the heet corr.

ducting metal :irohnil the enlosed heating elements 14. This confgn'natioii .best shown in Fig. Sonnof'the metiil is'jhol lowed out between elvnwnt-s. as indicated at 19, so that onl'vva relatively th-in-jiyfiortion of metal extends around and n ljueent the hottoml portion `of the heating elements 14.

'llovvever th'ernctiil increases in width contintrously as' the surface 'i2 is' approached. The under snriurre rises toV a: erestfhetiveen the elements 1li. The heat conducting properties Iof the inetul, in connection `with its configuration. unse substantially all of the heat generated to heiconie r-onoentrated at the 'top of the plate, where it is needed. endwno) great amount of heat is wnstefully rudiated' from the bottom surface. It is also another important advantage that the heating elements 14 may he readily ,slipped out and replaced while the `eoverl is' removed. I In oderto prevent the generation of injurious eddy currents in the metal'surroundinn the elements 14.j the electrical conductivity is interrupted b/"zagv cuts 2U through the bottom 'of portion 15, extending into the apertures 13. The leads 21 from the heating eienients are most conveniently assed through the apertures 22 located in tie extension 23 perfsa allel to the top surface 12,1and-.below the apertures for the heating units 14. This:

extension is most clearly shownin Fig. 4:.v

We claim: 1. In an electrical heating device, aheat conducting member having a plurality of ,conducting member being so formed that it encompasses substantially ,entirely each of,

tlie heating elements with a relatively thin amount of material on the side farthest from the surface to be heated, and with gradually and substantially uniformly increasing ma'- terial as this surface is approached.

2. In an electrical heating device, a heat conducting member havin an exposed surface which is 'to be heate and a plurality of heating elements embedded in the member, so arranged that the heat conducting material enveloping the heating elements increases gradually and substantially uniformly as the heated surface is approached from that locality which is farthest from-the heated surface.

3. In an electrical heating device, a metallic plate, an integral heating element housing disposed below said plate and provided with a plurality of arallel apertures adapted to receive the heating elements, said housing being provided below each aperture with a slot interrupting the continuity' of the metal around the aperture and a heating element in each aperture.

4. In an electrical heating device, a metallic plate, an integral heating element housing'disposedv below said plate and provided with a plurality of parallel apertures adapted to receive the heating elements, said housing having an undulating und fr surface rising to a crest between a pair of parallel apertures, and toward the pla-te, said undulating surface providing suoli a disposition of the material making up the housing that a gradually increasing thickness of material exists around each aperture from the point of the aperture farthest from the plate, towardv said plate.

In testimony whereof, we have hereunto set our hands.

. ARTHUR J. KERC-HER.

WILLIAM WESLEY HICKS. 

